Method for applying bumper strip to luggage piece

ABSTRACT

A method of applying a bumper strip to a luggage piece which has a frame member provided with an outwardly facing groove therein running around the luggage piece, the method comprising heating an initial length of material with a memory which is firm and resistant to compression at room temperature and which when heated is stretchable at the expense of a reduction in thickness and width and when cooled and unrestrained shrinks to its initial size and shape, the initial length of material having a width and thickness greater than the width and depth of the groove respectively, stretching the heated length of material to reduce its width to less than the groove width, applying the heated material in the groove in a manner to permit a measure of contraction but to preclude contraction to its initial length, and allowing the material to cool to contract same lengthwise while expanding same in width and thickness to fill the groove. Further the strip is formed of arcuate cross section and on cooling forms an arcuate cap hiding fasteners located in the groove. A luggage piece provided with a fastener hiding and groove filling bumper strip.

A United StatesPatent -S1an V [54] METHOD FOR APPLYING BUMPER STRIP TO LUGGAGE PIECE [72] lnventor: Jack Slan, Toronto, Ontario, Canada [73] Assignee: Dominion Luggage Co. Limited,

T Toronto, Ontario, Canada [22] Filed: March 2,1970

[21] Appl.No.: 15,804

Simms ..264/230 Primary Examiner-Robert F. White Assistant Examiner-Allen M. Sokal Attorney-Douglas S. Johnson @(IIIIIIIIII/I/ 451 Sept. 26, 1972 [57] ABSTRACT A method of applying a bumper strip to a luggage piece which has a frame member provided with an outwardly facing groove therein running around the luggage piece, the method comprising heating an initial length of material with a memory which is firm and resistant to compression at room temperature and which when heated is stretchable at the expense of a reduction in thickness and width and when cooled and unrestrained shrinks to its initial size and shape, the initial length of material having a width and thickness greater than the width and depth of the groove respectively, stretching the heated length of material to reduce its width to less than the groove width, applying the heated material in the groove in a manner to permit a measure of contraction but to preclude contraction to its initial length, and allowing the material to cool to contract same lengthwise while expanding same in'width and thickness to fill the groove. Further the strip is formed of arcuate cross section and on cooling forms an arcuate cap hiding fasteners located in the groove.

A luggage piece provided with a fastener hiding and groove filling bumper strip.

5 Claims, 4 Drawing Figures PMENTEDSEPZB I912 3.694. 540

. l N VENT OR.

JACK SLAN BY DQ462015 JoAnJ'o L- Attorney METHOD FOR APPLYING BUMPER STRIP TO LUGGAGE PIECE FIELD OF THE INVENTION I telegraphed throughthe bumper even after the bumper has been subjected to repeated impact overextended periods of use.

BACKGROUND or THE INVENTION I It is conventionalin luggage construction to form the luggage piece of a pair of opposing frames which are hingedtogether and are adapted to interfit when the case is closed and a pair of concave shells attached to these frames and forming the walls of the luggage piece. The shells are attached to the frames by various fastening means suchas rivets, staples or stitching and these fastening means, along with the other fastening means used for locks, hinges, etc., must be covered in order to provide a finished look to the luggage.

A the present the covering of the fasteners is achieved by glueing or securing a length of-binding strip overtop thereof. While this binding prevents the fasteners from being actually seen their presence is telegraphed through the binding strip, if not initially,

then just as soon as the binding is subjected to any im- I SUMMARY OF THE INVENTION It is the object of the present invention to provide a method of applying a luggage bumper to conceal fasteners such as those connecting the shells and the frames which will eliminate the present tedious steps of binding and'which will further result in a bumper which will both conceal the fasteners in a manner so that their presence will not be telegraphed therethrough even under repeated bumper impact and will provide a high degree of protection to the luggage piece.

More particularly according to the invention a luggage piece each of whose frames are provided with a peripheral groove within which the respective frame and shell fastening means are located has the bumper applied in such groove to overlie the fastening means as a bank or strip of normally hard but heat stretchable material which softens and becomes pliable under heat and which initially has at ambient room temperature a length less than the perimeter length of the frame groove and a width greater than the width of the groove, the bumper being heated to render it extensible and pliable and being stretched to increase its length and reduce its width and applied around the frame groove, the method utilizing the shrinkage of such band on cooling whereby it is cooled and shrunk around the frame into the groove causing it to expand in width to spread across the groove and to arch upwardly under the restraint applied by the groove width into a hard convex cap bridging the fastening means to prevent their presence being telegraphed therethrough and extending beyond the peripheral surfaces of the frame to provide a hard protective bumper surface highly resistant to impact.

As a result of the restraint against lateral spreading of .the cooling band imposedby the groove width causing arching of the band air is trapped beneath the band to additionally provide a measure of resilient cushioning against impact.

Preferably the side walls of each of the frame grooves is undercut and the applied bumper band on being cooled is caused to spread beneath the groove side walls into the undercuts to provide a positive and permanent interlock therewith.

BRIEF DESCRIPTION OF THE DRAWINGS These and other objects and features of the invention will be more fully understood from the following detailed description having reference to the accompanying drawings in which,

FIG. 1 is a perspective view of a luggage case of the type to'which a bumper is to be applied according to the invention, the bumper being shown in solid line in its initial state prior to heating softening and stretching and then its stretched state for application to the case.

FIG. 2 is a cross section of the bumper in its initial state.

FIG. 3 is a fragmented enlarged vertical cross-sectional view of a case of the type illustrated in FIG. 1 showing one of the bumpers in position after shrinkage and the other bumper ready for insertion into its respective groove after stretching.

FIG. 4 is an enlarged part vertical sectional part perspective view illustrating the relationship of the bumper, frame groove, and the fasteners holding the shells to the frame.

DETAILED DESCRIPTION OF THE DRAWINGS With reference to FIG. 1 there is shown a luggage piece I which is of the type as shown more particularly in FIGS. 2 and 3 comprising a pair of opposing frames 2 and 2a and shells 3 and 3a. Each of the frames 2 and 2a is shown provided with a peripheral groove 4 having the side walls 5 undercut as at 6. The shells 3 and 3a are secured to the frames 2 and 20 by fasteners 7 which may comprise staples as illustrated or rivets or stitching as desired. These fasteners connect the shells 3 and 3a to the frames through the bottom of the grooves 4. The frame 2 is shown with an inwardly depending leg 8 to which is anchored a tongue 9. The frame 2a has a corresponding inwardly projecting leg 8a provided at its inner end with a channel 10 which is adapted to receive the tonge 9 when the case is closed. It will be understood that the case sections comprised of the frames and shells 2 and 3 and 2a and 3a will be suitably hinged together so that they can be opened and closed in the usual manner and will be provided with suitable locks (not shown) which may also employ fasteners located in the grooves 4.

It will be appreciated that to provide a finished luggage piece, it is essential that the fasteners or staples 7 be covered and it is also important to provide protection against impact against the frames 2 and 2a to prevent their being dented or damaged. It has been the practice to glue in a covering strip and where undercut grooves are used to tuck such strip in underneath the sides of the groove requiring tedious and skilful handling of the binding strip. Moreover, the materials which can be worked with in such binding are normally readily compressed and if they are tightly applied over the fasteners or they are subject to impact the presence of the fasteners is telegraphed through the material. Also if not properly glued the cover strips quickly become loose.

According to the present invention these problems are overcome by forming the bumper strip designated at 11 from material such as polyvinyl chloride (PVC) which at normal or ambient room temperatures and below is relatively hard and rigid but which under the application of heat becomes pliable and stretchable, and on cooling has a memory causing it to contract towards its original size and shape. As a first step in providing the bumper according to the preferred process a length of material having the characteristics described is formed or molded into a closed band or ring 12 as illustrated in solid lines in FIG. 1 (and shown in cross section in FIG. 2) with its perimeter dimension about three quarters of the perimeter of the groove 4 into which it is intended to be inserted and with the width of the groove 4 including the width of the undercut portion thereof. Preferably the strip forming the ring 12 is arched in cross section and its edges are bevelled as at 13.

The band or ring 12 is heated which conveniently may be carried out by inserting into boiling water and when softened is stretched to the shape illustrated in dotted line at 22 in FIG. 1 to a perimeteral dimension greater than the perimeter of the frame into whose groove 4 it is to be inserted. It will be understood that the expansion of the bumper from the initial ring 12 to the ring 22 will be accomplished at the expense of reducing the thickness and width of the bumper strip 11 making up the ring 12 as illustrated atthe right in FIG. 3. The expansion of the ring 12 to the configuration 22 is exaggerated in the drawings for purposes of illustration. As will be appreciated it need only be stretched sufficiently so that it can be placed around the respective frame to be introduced into the groove 4. On release the ring has the tendency to snap into the groove like an elastic band.

After its introduction into the groove 4 the bumper is cooled and in cooling it shrinks and hardens into the ring configuration 32 illustrated at the left in FIG. 3. That is, in shrinking the width and the thickness of the strip 11 increases as the length decreases with the result that the strip first interlocks beneath the undercut side walls 5 and then as the strip width continues to expand the strip, in addition to attempting to return to its initial arched shape, is forced upwardly into a convex arc bridging over the fasteners 7. At the same time both the thickness and hardness increase and when the material of the bumper strip has cooled to ambient temperature it presents a hard bumper surface projecting outwardly beyond the respective frame and its arcuate shape effecting the bridging of the fasteners precludes the presence of the fasteners from being telegraphed through the strip.

In the course of its expansion into its arched formation a pocket 20 is formed beneath the ring 32 in which air is trapped and this air provides a resilient cushioning effect to assist in absorbing impacts on the bumper during use of the luggage.

While the preferred method of applying the bumper strip is to first form a strip of the appropriate material into a continuous ring as described. It will be understood that it is within the scope of the invention to simply apply the bumper as a strip without first forming it into ring.

In this connection by simply heating a strip of the appropriate material with a memory" such as PVC until it is pliable and stretchable one end may be fastened in the groove of the luggage frame such as groove 4 and while the strip is still hot and stretchable it may be drawn around the frame to lie more or less loosely in I the groove and when it has been so drawn around the frame the free end can then be fastened adjacent to the first fixed end. On cooling the strip will contract longitudinally and expand in width and thickness to lock into the groove in the same manner as previously described in respect of the ring 32.

Again while it would usually be desired to extend the bumper strip completely around the case it would not be essential to do so if the strip were applied as a strip rather than a continuous ring.

While in the preferred embodiment, the bumper strip is applied in an undercut groove it will be understood that the concept of expanding a heated strip to facilitate its placement in position and then cooling such strip to shrink lock in position can be applied in various other applications without departing from the invention or scope of the appended claims.

I claim:

1. A method of applying a bumper strip to a luggage piece having a frame member running around at least a substantial portion of the piece, said frame member having a groove having side walls formed therein, said method comprising heating an initial length of material which is firm and resistant to compression at room temperature and which when heated is stretchable at the expense of reduction in thickness and width, and when cooled and unrestrained shrinks to its initial size and shape prior to heating, said initial length of material having a width greater than the width of said groove, stretching said length of heated material, applying said material in stretched heated condition in said groove in a manner that upon cooling said material contracts in length while expanding in width and thickness until it is compressed between and bulges above the walls of said groove while at the same time constraining said length of material from contraction to its initial length.

2. A method as claimed in claim 1 in which said groove walls are undercut and said length of material is contracted longitudinally on cooling sufficiently to cause the edges of said length of material to expand beneath said undercut walls.

3. A method of applying a bumper strip to a luggage piece of the type comprising two hinged sections and in which each section comprises a peripheral frame and a shell attached thereto, the frame having a peripheral groove in the outerface thereof and means for fastening the shell to the frame projecting through the bottom of said groove, said groove being defined by a pair of spaced side walls, said method comprising heating a closed band of material having a perimeter less than the perimeter of the frame groove and a width greater than the spacing of said side walls, said material having the characteristics of being firm and resistant to compression at ambient room temperature and below and being stretchable at the expense of reduction in thickness and width upon heating and shrinkable on cooling to its original dimensions, stretching said closed band after heating to a perimeter greater than the groove perimeter and a width less than the spacing of said side walls, inserting said heated stretched band into said groove, and allowing said band to cool to shrink same peripherally into said groove to anchor band in said groove in fastening means covering relation, said band on cooling increasing in width to a width greater than the spacing between said side walls to effect a convex bulging of said band between said side walls to effect projection of said band beyond said side walls and to cause said band to bridge over said fastening means and to trap air therebeneath.

4. A method as claimed in claim 3 in which said side walls are undercut and said band is bevelled at the edges thereof to interlock under said undercut side walls on shrinkage.

5. A method as claimed in claim 3 in which said material is a polyvinyl chloride and is heated by boiling in water. 

2. A method as claimed in claim 1 in which said groove walls are undercut and said length of material is contracted longitudinally on cooling sufficiently to cause the edges of said length of material to expand beneath said undercut walls.
 3. A method of applying a bumper strip to a luggage piece of the type comprising two hinged sections and in which each section comprises a peripheral frame and a shell attached thereto, the frame having a peripheral groove in the outerface thereof and means for fastening the shell to the frame projecting through the bottom of said groove, said groove being defined by a pair of spaced side walls, said method comprising heating a closed band of material having a perimeter less than the perimeter of the frame groove and a width greater than the spacing of said side walls, said material having the characteristics of being firm and resistant to compression at ambient room temperature and below and being stretchable at the expense of reduction in thickness and width upon heating and shrinkable on cooling to its original dimensions, stretching said closed band after heating to a perimeter greater than the groove perimeter and a width less than the spacing of said side walls, inserting said heated stretched band into said groove, and allowing said band to cool to shrink same peripherally into said groove to anchor band in said groove in fastening means covering relation, said band on cooling increasing in width to a width greater than the spacing between said side walls to effect a convex bulging of said band between said side walls to effect projection of said band beyond said side walls and to cause said band to bridge over said fastening means and to trap air therebeneath.
 4. A method as claimed in claim 3 in which said side walls are undercut and said band is bevelled at the edges thereof to interlock under said undercut side walls on shrinkage.
 5. A method as claimed in claim 3 in which said material is a polyvinyl chloride and is heated by boiling in water. 